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Track and temperature changes

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el Gato Gordo View Drop Down
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    Posted: 22 Jun 2017 at 11:11am
In the current heat wave, I heard on the news that a freight train in California had derailed due to rails expanding in the extreme heat, and deforming all out of shape.

My layout is in my woodshop with no temperature control, but I have never had a problem, cold of winter or heat of summer.  Until now.  Tuesday afternoon, temps in the high 90's, temperature in the barn/woodshop 102°.  I ran a Regiobahn from my Bahnhof extension onto the main line and it ran in a curvy path - where it should have been straight!  Oh my!  It didn't derail, but I could see that the expansion from the heat had caused the flex track to buckle.

Wednesday morning the rails had contracted in the overnight coolness, and back to normal.  As a remedy, I cut the rails with my Dremel, offsetting the cuts on the two rails by a couple of inches so the wheels wouldn't hit the cuts at the same time.  This should provide enough of an expansion joint to prevent further distortion.  Now I need to solder new power leads onto the section of rails that was cut.

I'll report on how this works - it is supposed to get as hot again today.
Cheers!
Gordon
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Railwriter Quote  Post ReplyReply Direct Link To This Post Posted: 22 Jun 2017 at 12:33pm
Heat kinks are something prototype railroads have to deal with -- particularly on lines with welded rail.

Often it happens when one or more of these has happened
  • Rails were laid at the wrong temperature.  (If rails were laid on a very cold day, they expand much more on a hot day than if they were laid on a day that was already warm.  Often when welded rail is laid on cold days, it is heated before being fastened to the ties.)
  • The rail is not fastened securely enough to the ties.  This is particularly true in the case of wood ties, where you need to apply anchors at almost every tie on some critical sections.
  • The ties are not set solidly enough in the ballast (which otherwise would keep the ties from shifting due to expansion forces.
Of course, the opposite can happen, too, when in very cold weather welded rails (particularly if they have even a small internal flaw) may break apart due to contraction.

In Austria, many years ago, I was riding on an engine that was stopped due to a heat kink ahead.

Track workers were hauling buckets of cold water out of a nearby creek and pouring it on the rails.  Yes, really.  After a few minutes, we received clearance to proceed at reduced speed.

My understanding is that on most model railroads heat kinks are not a major problem, unless you have long sections of flex track that have been soldered to each other -- and the track has not been fastened solidly enough to the base below.  Though this would probably not be a problem with my layout, I am not soldering joints solid.  Instead, I am applying additional feeder wires -- in case the rail joiners do not provide a sufficient electrical connection.

-- Ernest

P.S.:  In German a track kink is called a "Gleisverwerfung"  or track distortion.


Edited by Railwriter - 22 Jun 2017 at 12:36pm
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el Gato Gordo View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote el Gato Gordo Quote  Post ReplyReply Direct Link To This Post Posted: 22 Jun 2017 at 1:31pm
Gleisverwerfung.  Thanks, Ernest.  I have been wondering how the railroads using welded rail deal with the issue; what kind of expansion joints do they use.

I built this layout - laid the track - in March, 2015, during a period of warm weather.  For Colorado in March, that would be 40° nights and 65-70° days.  Our temperature range here runs from about -5° F to 104° F, and I have not had a problem the past two summers.  The barn/woodshop has no kind of climate control.

This is my longest straight stretch of track: 72" of absolutely straight.  As mentioned, I cut a gap in each rail the width of a Dremel wheel.  I'll know in about two hours whether this fix worked.  Next layout I will follow you example and not solder all my track, as I did on this one.

Enjoyed your story about your experience in Austria - one wouldn't think of Austria as having that kind of problem.
Cheers!
Gordon
Rheinland Bayern Bahn
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